The present invention relates to devices for diagnosing internal disc disruption in intervertebral discs. More specifically, the present invention uses pressurized contrast media to distend a patient""s intervertebral disc and displays objective indicia of the existence of back pain and the existence and severity of Internal Disc Disruption (IDD).
Back pain can have a variety of causes, one of which is an internally injured intervertebral disc. Intervertebral discs are cushions of fibrocartilage between adjacent vertebrae of the spine. Each intervertebral disc is composed of a nucleus pulposis surrounded by an anulus fibrosus. When the nucleus pulposis degrades or is traumatically injured, fissures may form in the anulus fibrosus. An intervertebral disc degraded or injured in this fashion is said to have internal disruption. Fissures in the anulus fibrosus can cause back pain because: (1) the innervated outer section of the anulus fibrosus is injured and becomes painful when exposed to pressure; (2) the injured anulus fibrosus must bear the load previously supported by the healthy anulus fibrosus; and (3) the nerve endings in the fissured anulus fibrosus are exposed to the caustic and inflammatory intranuclear contents of the disc.
There is no reliable method or device in the prior art which can accurately diagnose a symptomatic and disrupted intervertebral disc. This is partly attributed to the fact that an internally disrupted intervertebral disc, unlike a herniated intervertebral disc, may not show any outward signs of abnormality. Thus, the most common diagnostic method, called disc stimulation or a discogram, is to inject saline or a contrast medium into the nucleus pulposis of an intervertebral disc suspected to be internally disrupted. The pressure of the injected fluid on the anulus fibrosus distends the intervertebral disc. If the intervertebral disc is not internally disrupted, the anulus fibrosus will withstand the pressure of the fluid and the patient should feel no pain. If the intervertebral disc is disrupted, the pressure of the injected fluid on the innervated section of the anulus fibrosus will reproduce the patient""s back pain. Thus, if the patient indicates that the pressurized injection causes the patient back pain, then the intervertebral disc which was injected is symptomatic.
However, this procedure has its drawbacks. First, there is no objective way to confirm the existence of pain. Thus, the procedure is entirely dependent on the patient""s ability to perceive and report the pain accurately.
Moreover, the prior art procedure only measures a single factor, the patient""s pain. In other words, disc stimulation has not previously provided objective measurements of the existence or severity of fissuring. Thus, disc stimulation used alone may misdiagnose an internally disrupted intervertebral disc because some condition other than an internally disrupted intervertebral disc may cause pain in the patient. While a CT x-ray scan may be performed after the disc stimulation to confirm fissuring in a intervertebral disc, disc stimulation must first be used to determine which intervertebral discs are symptomatic.
Thus, it is clear that there is a need in the art for an apparatus which provides objective measures of the presence of pain and the existence and degree of fissuring to diagnose, or confirm a diagnosis of, an internally disrupted intervertebral disc.
A device for diagnosing or confirming a diagnosis of a symptomatic internal disruption in an intervertebral disc in a patient""s spine is disclosed herein. A needle in fluid communication with a fluid source containing fluid contrast media is inserted into the patient""s spine so that the end of the needle rests in the nucleus pulposis of an intervertebral disc suspected to be disrupted. Contrast media is visible to an x-ray camera or a fluoroscope. The pressure of the contrast media delivered to the patient""s intervertebral disc is gradually increased.
Means are provided to measure the volume and pressure of the contrast media, take realtime videographic images of the patient""s facial expressions, obtain x-ray images of the patient""s intervertebral disc, and capture the patient""s vocalizations as the contrast media is injected into the patient""s intervertebral disc. In a preferred embodiment, a pressure sensor measures the pressure of the contrast media. Simultaneously, a video camera takes photographic images of the patient""s facial expressions, an x-ray camera takes x-ray images of the patient""s intervertebral disc, and a microphone captures the patient""s vocalizations. The pressure measurements, photographic images, x-ray images, and vocalizations are transmitted to a display. The display simultaneously and in real time displays on a single screen the photographic images, x-ray images, and pressure measurements. A speaker in the display also broadcasts the vocalizations. The present invention may include a video cassette recorder to record the displayed images and the patient""s vocalizations, a computer to digitally capture the displayed images and vocalizations, and a printer to prepare output copies of the displayed images.
A medical professional monitors the display. If the intervertebral disc is not internally disrupted, the patient should show no visible or audible indicia of pain such as uncomfortable or pained facial expressions or pained vocalizations. By contrast, if the intervertebral disc is symptomatically disrupted, the pressurized fluid will fill the fissures in the anulus fibrosus and press on the innervated outer section of the anulus fibrosis thereby reproducing the patient""s back pain. Thus, the patient""s pained facial expressions will be visible in the photographic images displayed and the patient""s pained vocalizations will be audible over the audio broadcast.
Also, if there is no fissuring, the intervertebral disc should be able to withstand a fluid pressure of at least 75 pounds per square inch, the pressure the intervertebral disc must bear during normal sitting or stooping. Conversely, if the intervertebral disc is internally disrupted, the intervertebral disc will be able to withstand much less pressure as the fissures are forced apart and, in the most severe cases, allow the contrast media to escape the intervertebral disc. A pain response at a pressure of less than 50-75 pounds per square inch would tend to indicate that the intervertebral disc is symptomatically disrupted.
Also, if there is no fissuring of the anulus fibrosus, the anulus fibrosus should contain the injected contrast media in the nucleus pulposis and the x-ray photographs should show no spreading of the contrast media beyond the horseshoe-shaped nucleus pulposis. If, however, the intervertebral disc is internally disrupted, the x-ray photographs will show the contrast media spreading through the fissures into the anulus fibrosus.
These measurements and images in combination are used by the medical professional to determine whether the intervertebral disc is internally disrupted. For example, a pain response at a pressure of less than 50-75 pounds per square inch in combination with x-ray images showing internal disc disruption would indicate that the intervertebral disc is symptomatically injured.
An object of the present invention is to provide a device which accurately and reliably diagnoses a symptomatic and disrupted intervertebral disc. It is a further object of the present invention to provide a medical professional with objective information in real time of the existence of pain in a patient and the existence and severity of fissuring in a patient""s intervertebral disc as the intervertebral disc is injected with contrast media. Also, it is an object of the present invention to provide objective data to confirm and support a medical professional""s conclusion and diagnosis. An additional object of the invention is to provide a display which simultaneously displays photographic images, x-ray images, and pressure readings on a single screen and provides an audio broadcast of the patient""s vocalizations so that a medical professional will be able to access all the relevant information without viewing numerous displays or switching between input channels on a display. A further object of the invention is to provide a device which can preserve the displays and audio broadcast for later use as evidence of the condition of the intervertebral disc. This allows other medical professionals to review the test results as if they were present at the time of the test. Another object of the invention is to standardize the parameters for diagnosis of internal disc disruption by decreasing interoperator variability in performing or interpreting the test.